Strategy

If you wander into Numara Atoll in disc 2, the chances of winning are low but possible. Recommend Seal/Lucky 0 Magic Damage, Poison, Double, Blind, as well as plenty of Angel's Plume.

If you make use of magic, it's not a problem to damage them. They just have WAY too much HP, and absolutely vicious attacks. All-Aquaus, for example, can do 2,000 damage to all characters if you're around level 25. If you return on disc 4 or so, you should be able to handle them. -- though it may still take a couple of turns.

To defeat the Hell Shaker easily you need to make sure mack has learned Splitter, and use it at the start of battle. It will half the Hell Shakers HP. Now here on in have your party cast the following spells in this order, Seal, Fear, Poison , and Virus. Then on your next turn, cast Shine and Slower. Then simply use Gamble until it dies.

The Hell Shaker is quite a tough monster, as it has 9120 HP and has very high resistance to physical attacks. If you want to finish it off quickly, give it status ailments like poison and seal, then stand by and wait for it to wear out. Poison drains 1140 HP for every round, which makes that its no. 1 weakness/susceptibility. (The Hell Shaker can be defeated at level 24 or 25, but to succeed in killing it at such a low level requires that you can be able to survive for long periods in battle. Gamble also has a potential of high damage.)

As stated above, use Poison (and/or Toxin and/or Virus) and Gamble. However, instead of using Seal (which just encourages the Hell Shaker to use Ground Shake -- which causes a significant amount of damage too), have Kaim and/or Seth use Attack. This causes the Hell Shakers spell to be delayed giving you plenty more chances to kill it with Gamble.

Suggested start at about level 25. Have Kaim in the front to absorb damage, and the other four characters using magic. As stated above use poison and virus, (toxin if you have it) on the first turn, couple this with terror so that it's less likely to attack, and blinding isn't bad either as "ground shake" is less likely to hit everyone. Keep him from using All-Aquaus by casting seal after he seems to have missed a turn, the missed turn is the charge. If you do seal him as he charges he will waste 2 turns, that could be the key to victory in this fight. Continue to throw out toxin every now and then as it wears off, and throw in some more status aliments to make the fight easier.

-This is a great way to level grind as you level up each time you defeat one, up to about level 40. You can get to 50 but exp gain slows down a bit.